Joseph Masabni, Assistant Professor and Extension Horticulturist, The Texas A&M University System
Turnips and mustards, members of the cabbage family, are cool-season crops. They must be grown in the cool temperatures of early spring and fall.
Mustard is grown only for the leaves. Turnip is a dual purpose crop—the leaves are used for greens, and the root is cooked similar to potatoes and beets. When cooked properly, mustard and turnip greens are high in minerals and vitamins A and C.
Turnips can be used either for greens or for roots. A variety developed for root production can be harvested for greens. However, a variety developed for greens may not produce a good root. Mustard varieties can be broadleaved or curled. Broadleaved mustard has a wide, flat leaf. Curled leaf mustard produces narrow, wrinkled leaves like those of spinach.
Curled mustard will stand colder temperatures and can be grown later into the winter than can broadleaved mustard. Some gardeners do not like curled mustard because it is hard to wash sand and dirt from the wrinkled leaves. A well-mulched garden usually does not have this problem.
If possible, plant mustard and turnips in full sun. For best production, they also need well-drained soil.
Mustard works well as a border to a flower bed or sidewalk (Fig. 1). Both the broadleaf and curled leaf varieties are attractive and add green to a flower bed. Mustard and turnip greens are also easily grown in window boxes and containers on an apartment balcony or patio.
Plant turnips and mustards as soon as the soil can be worked in the spring. The seeds will sprout if the soil temperature is 40 degrees F or higher.
For a fall crop, start planting 8 to 10 weeks before the first expected frost. In South Texas and coastal areas, turnips and mustard grow well all winter. Bed the soil into ridges 6 to 8 inches high and 18 to 24 inches apart (Fig. 2). Allow the ridges to settle, or pack them before planting. Just before planting, drag the top from the ridges with a rake or hoe to widen the planting bed to 8 to 10 inches (Fig. 3).
If the ridges have been made 3 feet apart for planting other vegetables, plant two rows of mustard and turnips on each ridge. You can plant one row of seeds down each side of the ridge.
Plant the seeds in moist soil. This is vital for fall crops. Cover the seeds lightly with soft soil or compost; then sprinkle the row with water to speed sprouting. When planting a fall crop, cover the seeds with sand or light-colored mulch to keep the row cool.
Sprinkle the row regularly with water to prevent soil crusting until the small plants break through. Under good conditions, most of the plants should be up in 3 to 7 days.
To have a continuous supply of fresh, tender mustard and turnip greens, make two or three plantings 10 days apart.
Before planting mustard or turnips, till the soil then scatter 2 to 3 pounds of complete garden fertilizer such as 15-5-10 over each 100 square feet (Fig. 4). If only one row is to be planted, use 1 cup of fertilizer for each 10 feet of row (Fig. 5.) Phosphorus, the middle number on the fertilizer bag, is especially needed to grow good turnip roots.
Care during the season
Keep the plants free of weeds, especially when they are small. Pull the weeds by hand or use a hoe, but do not cut too deeply with the hoe, or you may cut of the some crop roots.
When the plants become crowded in the row, thin the row by pulling some plants. Small plants of both turnips and mustard make delicious greens. Thin the mustard plants until they are about 6 inches apart (Fig. 6). Leave the turnips 3 to 4 inches apart; remember that overcrowding prevents the turnip roots from developing.
Turnips and mustards need adequate nitrogen to develop a dark green color. When the plants are 4 to 5 inches tall, apply ½ cup of fertilizer for each 10 feet of row. Spread the fertilizer beside the plants, mix it lightly with the soil and water it into the soil. If the soil is sandy and the season is wet, apply more fertilizer later.
Many insecticides are available at garden centers. Sevin is a synthetic insecticide; organic options include sulfur and Bt-based insecticides. Sulfur has also fungicidal properties and helps in controlling many diseases.
Before using a pesticide, read the label and always follow cautions, warnings, and directions. Because greens are harvested often, be sure to follow the waiting periods for pesticides.
Diseases on turnips are most severe in cloudy, damp weather. Check the plants daily; if diseases appear, treat the plants with an approved fungicide. Neem oil, sulfur, and other fungicides are available for use. Always follow label directions.
Mustard and turnip greens are good until the weather gets hot. Too much heat causes them to be tough and strong flavored. Harvest mustard greens when they are young and tender. Cut the large outer leaves and leave the inner leaves to continue growing. You can also cut and use the entire plants.
Most turnip varieties produce greens in 40 days. Turnip roots generally take 50 to 60 days to produce. Harvest turnip greens by pulling the entire plant when the leaves are 4 to 6 inches long (Fig. 7a.) Turnip roots can be harvested when they are 2 to 2½ inches in diameter (Fig. 7b). If left longer they will get tough and stringy.
The ideal size of turnip roots harvested for bunching is 2 inches in diameter. If you want to top the turnip roots, the bigger roots that are 3 to 4 inches in diameter are best suited for this method. Both mustards and turnips lose quality and go to seed quickly when days become long and hot. Do not leave them too long.
Unused leafy vegetables make good additions to a compost pile. They break down quickly and can be turned into the garden soil.
Greens can be stored several days in closed plastic bags in the refrigerator. Turnip roots will keep several weeks in a cool, humid area such as a root cellar or the bottom of the refrigerator.
Cook greens only until they are tender. Use only the water that remains on the leaves after washing them. For more information on how to prepare and serve mustards and turnips, contact your county Extension agent.
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